Means for cooling powder-burning combustion chambers and nozzles



Sept. 12, 1950 R. H. GODDARD MEANS FOR COOLING POWDER-BURNING COMBUSTION CHAMBERS AND NOZZLES FiledJan. z, 1948 lNVEN'l OR.

ATTORNEYS.

Patented Sept. 12, 1950 MEANS FOR COOLING POWDER-BURNING COMBUSTION CHAMBERS AND NOZZLES Robert H. Goddard, deceased, late of Annapolis,

Md., by Esther ter, Mesa, ass

0. Goddard, executrix, Worcesanor oi one-hall to The Daniel and Florence Guggenheim Foundation, New York, N. Y., a corporation oi New York Application January 2, 1948, Serial No. 81

t Claims. Gil-85.8)

This invention relates to powder-burning combustion chambers as used in rockets and other propulsion apparatus. In such apparatus, combustion of the relatively slow-burning powder charge exposes the rearwardly directed discharge nozzle and the adjacent parts of the combustion chamber to very high temperature for a considerable period of time. This presents the possibility of burning and erosion of the exposed surfaces.

It is the general object of the present invention to provide improved means for cooling the nozzle and the adjacent chamber parts during the combustion of such a relatively'slow-burning powder charge.

A further object is to provide means by which the combustion of the powder charge automatically develops pressure to spray these exposed surfaces with water, or with a mixture of water and steam.

The invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawing, in which Fig. 1 is a sectional side elevation of a combustion chamber and nozzle embodying this invention; and

Figs. 2 and 3 are partial perspective views of a powder casing and sealing ring to be described.

Referring to the drawing, a cylindrical combustion chamber C and an associated nozzle N are shown. The chamber 0 is preferably provided with a removable cap it, which may be threaded to the inner end of the chamber wall as shown in 18. 1.

A powder charge P is contained within a cylindrical metal casing I! having an inner closed end It and having the opposite end freely open. The casing I2 is of somewhat smaller diameter than the combustion chamber C and iscentered in v the chamber by a sealing ring 20 at the open end and by spaced pins or lugs 2| near the closed end. The ring 20 is a close sliding lit in the chamber 0 and the pins or lugs Il may have relatively free sliding engagement with the chamber C. The

ring 20 may be integral with the casing H or may be separately formed and permanently secured thereto.

The sealing ring 20 has aplurality of spirally disposed openings 24 which are arranged in a circumferential series and which are each normally filled by a plug of a soft but water-proof composition which may be forced out of the opening 24 by the application of moderate pressure.

The space between the cap Ill and the cylinder end I4 and also the annular space between the casing I2 and the chamber C is filled with water W after the powder charge is placed in the chamber, the charge being located axially by stop pins 30. The chamber may be conveniently filled when in a vertical position, after which the cap i0 is firmly secured in place.

The powder charge P may be ignited by a hot wire R or in any other convenient manner. As soon as the charge P is ignited, combustion gases will be developed in the outer end portion of the combustion chamber C and will be discharged through the restricted passage connecting the chamber 0 to the nozzle N.

The reactive force of the combustion gases will be exerted against the powder charge P and will tend to move the casing l2 and ring 20 to the left in Fig. 1 and to thus put the cooling water W under pressure.

As this pressure is built up, the soft composition plugs which close the spiral openings 24 will be forced out, whereupon a circumferential series of substantially tangential sprays oi water will be ejected through the openings 24 and will form a cooling film on the exposed wall surfaces of the chamber C and nozzle N.

This spray will continue as the casing I2 is forced further to the left in Fig. 1 and until the casing I2 engages the cap iii. If the parts are correctly proportioned, the powder charge will be substantially consumed by the time the casing end it engages the cap in and the supply of cooling liquid has been exhausted.

Having thus described the invention and the advantages thereof, it will be understood that the invention is not to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what is claimed is:

1. In propulsion apparatus, a cylindrical combustion chamber having a rearwardly directed discharge nozzle, a metal casing loosely slidable in said combustion chamber and containing a powder charge, said casing being closed at its inner end and open toward said nozzle, and a sealing ring mounted on said casing at its open end and closely fitting said cylindrical combustion chamber and confining a cooling liquid between said casing and said chamber wall and inner end, said sealing ring having passages therethrough for escape of the cooling liquid and said passages being normally closed by pressure-displaceable plugs.

2. The combination in propulsion apparatus as set forth in claim 1, in which the passages in the sealing ring are spirally disposed to give the coola 3 ing sprays discharged therethrouah a. substantially tangential rotating motion.

3. The combination in propulsion apparatus as set forth in claim 1, in which stops are provided to limit outward movement of said casing in said combustion chamber.

4. In propulsion apparatus, a cylindrical oombustion chamber having a rearwardiy directed discharge nozzle, a container for a charae of explosive mounted to slide freely axially inward of said chamber on ignition 01' said explosive and development of gas pressure in said nomle, and said combustion chamber having an annular longitudinal passage about said container provided with a closure and spray openings at its outer end and adjacent said nozzle, whereby a supply of cooling liquid confined in said combustion chamber at its inner end by said container will be ejected through said passage and spray openlogs on inward sliding movement 0! said 0011- 20 tainer by the gas pressure developed in the outer" 5 Executria: o] the last will and testament of Robert H. Goddard, deceased.

REFERENCES CITED The following references are 0! record in the l file of this patent:

UNITED sums Pam'rs Number Name Date 1,881,582 Wenstrom Aug. 21, 1928 15 2,444,957 Skinner July 13, 1948 FOREIGN PA'IWTB Number Country Date 477,022 France June 24, 1916 

